Energy Flashcards
What is a system?
An object or group of objects.
What is the equation for kinetic energy?
Kinetic Energy=0.5 × mass ×
velocity²
Ek = ½ m v²
What is the equation for elastic potential energy?
Elastic potential energy=0.5 × spring constant × extension²
Ee = ½ k e²
What is the unit for spring constant?
N/m
What is the equation for gravitational potential energy?
Gravitational potential energy= mass × gravitational field strength × height
Ep = m g h
What is the gravitational field strength of earth?
9.8 N/kg
What is the equation for change in thermal energy?
Change in thermal energy = mass × specific heat capacity
× temperature change
E = m c ∆θ
What are the equations for power?
Power = energy transferred /
time
P = E / t
Power = work done / time
P = W / t
In terms of energy, what is power?
1 watt = 1 joule per second
1 W = 1 J/s
How can energy be transferred?
Usefully, stored or dissipated but not created or destroyed.
Energy that is not useful and dissipated to the surroundings is?
Wasted
What are some methods to reduce unwanted energy transfer?
Lubrication, thermal insulation.
The higher the thermal conductivity of a substance the higher the?
The rate of energy transfer through conduction.
What is the equation for efficiency?
Efficiency = useful output energy / total input energy
What are the main energy resources available on earth?
- Fossil Fuels
- Nuclear
- Biofuel
- Wind
- Hydroelectric
- Geothermal
- Tidal
- Sun light
- Waves
